Impact of the graphic Canadian warning labels on adult smoking behaviour.

OBJECTIVE: To assess the impact of graphic Canadian cigarette warning labels on current adult smokers.

DESIGN: A random-digit-dial telephone survey was conducted with 616 adult smokers in south western Ontario, Canada in October/November 2001, with three month follow up.

MAIN OUTCOME MEASURES: Smoking behaviour (quitting, quit attempts, and reduced smoking), intentions to quit, and salience of the warning labels.

RESULTS: Virtually all smokers (91%) reported having read the warning labels and smokers demonstrated a thorough knowledge of their content. A strong positive relation was observed between a measure of cognitive processing-the extent to which smokers reported reading, thinking about, and discussing the new labels-and smokers' intentions to quit (odds ratio (OR) 1.11, 95% confidence interval (CI) 1.07 to 1.16; p < 0.001). Most important, cognitive processing predicted cessation behaviour at follow up. Smokers who had read, thought about, and discussed the new labels at baseline were more likely to have quit, made a quit attempt, or reduced their smoking three months later, after adjusting for intentions to quit and smoking status at baseline (OR 1.07, 95% CI 1.03 to 1.12; p < 0.001).

CONCLUSIONS: Graphic cigarette warning labels serve as an effective population based smoking cessation intervention. The findings add to the growing literature on health warnings and provide strong support for the effectiveness of Canada's tobacco labelling policy.